function [C, sigma] = dataset3Params(X, y, Xval, yval)
%EX6PARAMS returns your choice of C and sigma for Part 3 of the exercise
%where you select the optimal (C, sigma) learning parameters to use for SVM
%with RBF kernel
%   [C, sigma] = EX6PARAMS(X, y, Xval, yval) returns your choice of C and 
%   sigma. You should complete this function to return the optimal C and 
%   sigma based on a cross-validation set.
%

% You need to return the following variables correctly.
C = 1;
sigma = 0.3;

% ====================== YOUR CODE HERE ======================
% Instructions: Fill in this function to return the optimal C and sigma
%               learning parameters found using the cross validation set.
%               You can use svmPredict to predict the labels on the cross
%               validation set. For example, 
%                   predictions = svmPredict(model, Xval);
%               will return the predictions on the cross validation set.
%
%  Note: You can compute the prediction error using 
%        mean(double(predictions ~= yval))
%  model = svmTrain(X, y, C, @(x1, x2) gaussianKernel(x1, x2, sigma));
values = [0.01 0.03 0.1 0.3 1 3 10 30]
min_error = Inf

for i = values,
	for j = values,
		x1 = [1 2 1]; x2 = [0 4 -1];
		model = svmTrain(X, y, i, @(x1, x2) gaussianKernel(x1, x2, j));
		predictions = svmPredict(model, Xval);
		error = mean(double(predictions ~= yval))
		if error < min_error,
			min_error = error;
			C = i;
			sigma = j;
		end
	end
end

fprintf('Best C : %f\n',C);
fprintf('Best sigma : %f\n',sigma);




% =========================================================================

end
